View Full Version : New to the FS700 Trying to understand how to correctly set exposure in slow mo


Mike Dempsey
July 10th, 2014, 04:37 PM
Hello friends,

I recently got my fs700 and I am having trouble understanding how to set exposure in slow motion modes. I am completely new to the camera but when I enter into 240, 480, 940 frame rates the lighting goes down as expected. I understand the concept behind why but I can't figure out how to compensate for that loss. The only thing that I've been able to come up with is turning the ISO way up but it makes the image look pretty awful. I've seen people shooting in lower light than I have been in my test footage and theirs is quite crisp. Can anyone recommend some settings, tips, or links that I could learn from?

Thanks,
Mike

Alister Chapman
July 11th, 2014, 12:49 AM
Getting more light on to the sensor is the best solution.

This can be done by using either a faster lens with a larger aperture, maybe a full frame Canon/Nikon DSLR lens with a metabones speed booster or simply by adding more light in to the scene with lights or reflectors.

Any other camera settings will introduce noise or other artefacts.

Colin Elves
July 11th, 2014, 01:20 PM
What Alister said. You might also want to check that you've not got the ND on! The other possibility may be they used noise reduction or a different picture profile (although the 'faster' profile tend to add a lot of noise themselves.) 960fps is pretty hefty in terms of light needed though, all else being equal you need at least another 4 1/2 stops of light over 24fps!

Alister Chapman
July 15th, 2014, 03:33 AM
Assuming 360 degree shutter, 24fps to 240fps is just over 3 stops, 24fps to 480fps is a bit over 4 stops and 960fps is over 5 stops.

If you start with 1/48th shutter at 24fps and then turn the shutter off for the others reduce by one stop.

So if 1 LED panel or 1 lamp is OK at 24fps with 1/48th shutter, with shutter off you will need:

AT LEAST 4 lamps for 240fps, 8 lamps for 480fps and 16 for 960fps.